/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.xerces.util;


Shadowed symbol table.
The table has a reference to the main symbol table and is 
not allowed to add new symbols to the main symbol table. 
New symbols are added to the shadow symbol table and are local 
to the component using this table.
Author:
Andy Clark IBM
Version:
$Id: ShadowedSymbolTable.java 447241 2006-09-18 05:12:57Z mrglavas $/**
 * Shadowed symbol table.
 *
 * The table has a reference to the main symbol table and is 
 * not allowed to add new symbols to the main symbol table. 
 * New symbols are added to the shadow symbol table and are local 
 * to the component using this table.
 * 
 * @author Andy Clark IBM
 * @version $Id: ShadowedSymbolTable.java 447241 2006-09-18 05:12:57Z mrglavas $
 */

public final class ShadowedSymbolTable
extends SymbolTable {

    //
    // Data
    //

    
Main symbol table. /** Main symbol table. */
    protected SymbolTable fSymbolTable;

    //
    // Constructors
    //

    
Constructs a shadow of the specified symbol table. /** Constructs a shadow of the specified symbol table. */
    public ShadowedSymbolTable(SymbolTable symbolTable) {
        fSymbolTable = symbolTable;
    } // <init>(SymbolTable)

    //
    // SymbolTable methods
    //

    
Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. If the symbol already exists, 
the previous symbol reference is returned instead, in order
guarantee that symbol references remain unique.
Params:
symbol – The new symbol./**
     * Adds the specified symbol to the symbol table and returns a
     * reference to the unique symbol. If the symbol already exists, 
     * the previous symbol reference is returned instead, in order
     * guarantee that symbol references remain unique.
     * 
     * @param symbol The new symbol.
     */
    public String addSymbol(String symbol) {

        if (fSymbolTable.containsSymbol(symbol)) {
            return fSymbolTable.addSymbol(symbol);
        }
        return super.addSymbol(symbol);

    } // addSymbol(String)

    
Adds the specified symbol to the symbol table and returns a
reference to the unique symbol. If the symbol already exists, 
the previous symbol reference is returned instead, in order
guarantee that symbol references remain unique.
Params:
buffer – The buffer containing the new symbol.
offset – The offset into the buffer of the new symbol.
length – The length of the new symbol in the buffer./**
     * Adds the specified symbol to the symbol table and returns a
     * reference to the unique symbol. If the symbol already exists, 
     * the previous symbol reference is returned instead, in order
     * guarantee that symbol references remain unique.
     * 
     * @param buffer The buffer containing the new symbol.
     * @param offset The offset into the buffer of the new symbol.
     * @param length The length of the new symbol in the buffer.
     */
    public String addSymbol(char[] buffer, int offset, int length) {

        if (fSymbolTable.containsSymbol(buffer, offset, length)) {
            return fSymbolTable.addSymbol(buffer, offset, length);
        }
        return super.addSymbol(buffer, offset, length);

    } // addSymbol(char[],int,int):String

    
Returns a hashcode value for the specified symbol. The value
returned by this method must be identical to the value returned
by the hash(char[],int,int) method when called
with the character array that comprises the symbol string.
Params:
symbol – The symbol to hash./**
     * Returns a hashcode value for the specified symbol. The value
     * returned by this method must be identical to the value returned
     * by the <code>hash(char[],int,int)</code> method when called
     * with the character array that comprises the symbol string.
     * 
     * @param symbol The symbol to hash.
     */
    public int hash(String symbol) {
        return fSymbolTable.hash(symbol);
    } // hash(String):int

    
Returns a hashcode value for the specified symbol information. 
The value returned by this method must be identical to the value
returned by the hash(String) method when called
with the string object created from the symbol information.
Params:
buffer – The character buffer containing the symbol.
offset – The offset into the character buffer of the start
              of the symbol.
length – The length of the symbol./**
     * Returns a hashcode value for the specified symbol information. 
     * The value returned by this method must be identical to the value
     * returned by the <code>hash(String)</code> method when called
     * with the string object created from the symbol information.
     * 
     * @param buffer The character buffer containing the symbol.
     * @param offset The offset into the character buffer of the start
     *               of the symbol.
     * @param length The length of the symbol.
     */
    public int hash(char[] buffer, int offset, int length) {
        return fSymbolTable.hash(buffer, offset, length);
    } // hash(char[],int,int):int

} // class ShadowedSymbolTable